Scientific research aboard the International Space Station will significantly expand the number of science investigations during Expedition Four, and new equipment will make the research outpost even more productive.

The Station's fourth crew was launched to the Station aboard Space Shuttle Endeavour (STS-108) on Dec. 5, 2001. Their five-month mission will end when Endeavour (STS-111) returns to the Station with a new crew and lands May 13, 2002, with the Expedition Four team. Expedition Four will include an additional Shuttle flight (STS-110) in March 2002 and one Russian Progress cargo flight. Both STS-108 and STS-111 will carry Multi Purpose Logistics Modules, developed for the Station program to carry payload racks, scientific equipment and other supplies to
sustain the Station and its crew.

Several new experiments and science facilities will be ferried to the orbiting outpost during Expedition Four. The research complement will grow from 18 to 26 NASA payloads, seven of them new to the ISS Program - two in fundamental biology, seven in human life sciences, six in microgravity science, six in space product development, and five sponsored by the Office of Space Flight.

New experiments are expected to lead to new insights in the fields of plant growth, embryo development, the longterm effects of spaceflight on humans, biotechnology, medicine, agriculture, electronics and pharmaceutical manufacturing. Several experiments begun on earlier Expeditions will return to Earth, while several others will continue operating during Expedition Four.

The three Expedition Four crewmembers are scheduled to devote nearly 500 hours to research. Those are in addition to the hours devoted by the Station's ever-present "fourth crewmember" - controllers and scientists on the ground who will continue to plan, monitor and operate experiments from the control centers around the country. In addition, the autonomous payloads will accrue several thousand hours of operational time.

Expedition Four crewmembers are Commander Yuri Onufrienko of Russia and U.S. Flight Engineers Carl Walz and Dan Bursch. They will continue maintaining the Space Station, adding to its capabilities and working with science teams on the ground to operate experiments and collect data.

On Earth, a new cadre of controllers for Expedition Four will replace their Expedition Three colleagues in the International Space Station's Payload Operations Center at NASA's Marshall Space Flight Center in Huntsville, Ala. Controllers work in three shifts around the clock, seven days a week in the Payload Operations Center, the world's primary science command post for the Space Station. Its mission is to link Earth-bound researchers around the world with their experiments and crew aboard the Space Station.

New Experiments

Expedition Four Shuttle flights will bring with them several new experiments, as well as experiments making repeat flights aboard the Station to continue their research. These include:

Biomass Production System (BPS) and Photosynthesis Experiment and System Testing Operation (PESTO): The main goal of BPS is to validate equipment necessary to grow wheat and Brassica in microgravity and eventually develop a dedicated Plant Research Unit for the Space Station. The secondary objective is to study the effects of microgravity on wheat photosynthesis and metabolism.

Avian Development Facility (ADF): Remaining on board the Shuttle during the UF1 flight, this experiment will be used to incubate 36 Japanese quail eggs and fix the embryos for a postflight, biospecimen-sharing program.

Astronauts in EVA Radiation Study (EVARM): Spacewalking astronauts will wear three active dosimeter badges in pockets sewn into their spacesuits to determine the levels of radiation received to the skin, eyes and blood-forming organs.

The ADVANCED ASTROCULTURE is the first facility being used to grow plants on the Space Station. (NASA/MSFC)

Advanced Astroculture 02 (ADVASC): A re-flight of an Expedition Two experiment facility, this commercial endeavor will be used to grow Arabidopsis from seed to maturity. A new feature on this flight will be the capability to collect samples of the growing plants while they're growing in space.

Commercial Generic Bioprocessing Apparatus (CGBA): A reflight of the Expedition Two experiment looking at bacterial fermentation and antibiotic production in space. Commercial Biomedical Testing Module (CBTM): This experiment will help determine the effectiveness of a natural protein called osteoprotegerin as a possible countermeasure for osteoporosis. This "sortie" experiment will remain aboard the Shuttle on the UF1 flight.

Zeolite Crystal Growth Furnace (ZCG): The goal of this commercial experiment is to grow larger crystals in microgravity with possible applications in chemical processes, electronic device manufacture and other applications on Earth.

Experiment on Physics of Colloids in Space, a fluids experiment that could lead to new materials and products. Colloids are found in numerous products, such as paint, milk, ink, copy machine toner and are used in many manufacturing processes, such as polishing silicon for computer chips and removing bitter tastes from wine and fruit juices;

Using the Internet and a digital camera mounted to the Space Station's laboratory window, EarthKAM students are able to take stunning, high-quality photographs of our planet, such as this image of Transylvannia, taken May 2001. (NASA)

Earth Knowledge Acquired by Middle school students, a program that lets students take pictures using an electronic camera on the Space Station. Students use the Internet to assign targets to the Station camera and receive pictures, which they then use in a variety of classroom projects;

Hoffman Reflex, an experiment to study changes in neurovestibular function with the goal of determining if exercise could be made more effective on longterm space flights;

Crew Interactions experiment to identify and characterize interpersonal and cultural factors that may affect crew and ground support personnel performance during Space Station missions;

Cell Biotechnology Operations Support Systems (CBOSS) used to grow three-dimensional tissue that retains the form and function of natural living tissue, a capability that could hold insights in studying human diseases, including various types of cancer, diabetes, heart disease and AIDS;

Xenon 1, a study of blood flow and ability of the body to adjust to the return to Earth after space flight;

Backdropped by a sunrise, the newly installed Materials International Space Station Experiment (MISSE) is visible on the International Space Station. (NASA/JSC)

Materials International Space Station (MISSE) experiment, attached to the outside of the Space Station to expose hundreds of sample materials to the space environment. By examining how the coatings fare in the harsh environment of space, researchers seek new insight into developing materials for future spacecraft, as well as making materials last longer on Earth.

Returning Experiments

Four payloads or sets of experiment samples are returning to Earth on STS-108 at the end of Expedition Three. Cell tissue growth samples grown on the Space Station during Expedition Three as part of the Cellular Biotechnology Operations Support System and biological materials grown in the Dynamically Controlled Protein Crystal Growth experiments will be returned to Earth for study, while the experiment hardware remains on board to process additional samples during Expedition Four. A pair of Expedition Three experiments, the Advanced Protein Crystallization Facility and the Dreamtime High Definition TV camera, will be returned to Earth.